/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.jbpm.compiler.xml.compiler.rules;

import org.drools.drl.ast.descr.FunctionDescr;
import org.drools.drl.ast.descr.PackageDescr;
import org.jbpm.compiler.xml.Handler;
import org.jbpm.compiler.xml.Parser;
import org.jbpm.compiler.xml.core.BaseAbstractHandler;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;

/**
 *
 * TODO To change the template for this generated type comment go to Window -
 * Preferences - Java - Code Style - Code Templates
 */
public class FunctionHandler extends BaseAbstractHandler
        implements
        Handler {
    public FunctionHandler() {
    }

    public Object start(final String uri,
            final String localName,
            final Attributes attrs,
            final Parser parser) throws SAXException {
        parser.startElementBuilder(localName,
                attrs);
        final String name = attrs.getValue("name");
        final String returnType = attrs.getValue("return-type");

        emptyAttributeCheck(localName, "name", name, parser);
        emptyAttributeCheck(localName, "return-type", returnType, parser);

        return new FunctionDescr(name, returnType);
    }

    public Object end(final String uri,
            final String localName,
            final Parser parser) throws SAXException {
        final Element element = parser.endElementBuilder();

        FunctionDescr functionDescr = (FunctionDescr) parser.getCurrent();

        final NodeList parameters = element.getElementsByTagName("parameter");

        for (int i = 0, length = parameters.getLength(); i < length; i++) {
            final String identifier = ((Element) parameters.item(i)).getAttribute("identifier");
            final String type = ((Element) parameters.item(i)).getAttribute("type");

            emptyAttributeCheck("parameter", "identifier", identifier, parser);
            emptyAttributeCheck("parameter", "type", type, parser);

            functionDescr.addParameter(type,
                    identifier);
        }

        // we allow empty, "", bodies - but make sure that we atleast have a body element

        NodeList list = element.getElementsByTagName("body");
        if (list.getLength() == 0) {
            throw new SAXParseException("function must have a <body>",
                    parser.getLocator());

        }

        functionDescr.setText(((org.w3c.dom.Text) list.item(0).getChildNodes().item(0)).getWholeText());

        final PackageDescr packageDescr = (PackageDescr) parser.getData();

        packageDescr.addFunction(functionDescr);

        return functionDescr;
    }

    public Class generateNodeFor() {
        return FunctionDescr.class;
    }
}
